X-Ray Fluorescence Spectroscopy for Laboratory Applications

Preface xvii List of Abbreviations and Symbols xix About the Authors xxiii 1 Introduction 1 2 Principles of X-ray Spectrometry 7 2.1 Analytical Performance 7 2.2 X-ray Radiation and Their Interaction 11 2.2.1 Parts of an X-ray Spectrum 11 2.2.2 Intensity of the Characteristic Radiation 13 2.2.3 Nomenclature of X-ray Lines 15 2.2.4 Interaction of X-rays with Matter 15 2.2.4.1 Absorption 16 2.2.4.2 Scattering 17 2.2.5 Detection of X-ray Spectra 20 2.3 The Development of X-ray Spectrometry 21 2.4 Carrying Out an Analysis 26 2.4.1 Analysis Method 26 2.4.2 Sequence of an Analysis 27 2.4.2.1 Quality of the Sample Material 27 2.4.2.2 Sample Preparation 27 2.4.2.3 Analysis Task 28 2.4.2.4 Measurement and Evaluation of the Measurement Data 28 2.4.2.5 Creation of an Analysis Report 29 3 Sample Preparation 31 3.1 Objectives of Sample Preparation 31 3.2 Preparation Techniques 32 3.2.1 Preparation Techniques for Solid Samples 32 3.2.2 Information Depth and Analyzed Volume 32 3.2.3 Infinite Thickness 36 3.2.4 Contaminations 37 3.2.5 Homogeneity 38 3.3 Preparation of Compact and Homogeneous Materials 39 3.3.1 Metals 39 3.3.2 Glasses 40 3.4 Small Parts Materials 41 3.4.1 Grinding of Small Parts Material 42 3.4.2 Preparation by Pouring Loose Powder into a Sample Cup 43 3.4.3 Preparation of the Measurement Sample by Pressing into a Pellet 44 3.4.4 Preparation of the Sample by Fusion Beads 48 3.4.4.1 Improving the Quality of the Analysis 48 3.4.4.2 Steps for the Production of Fusion Beads 49 3.4.4.3 Loss of Ignition 53 3.4.4.4 Quality Criteria for Fusion Beads 53 3.4.4.5 Preparation of Special Materials 54 3.5 Liquid Samples 55 3.5.1 Direct Measurement of Liquids 55 3.5.2 Special Processing Procedures for Liquid Samples 58 3.6 Biological Materials 58 3.7 Small Particles, Dust, and Aerosols 59 4 XRF Instrument Types 61 4.1 General Design of an X-ray Spectrometer 61 4.2 Comparison of Wavelength- and Energy-Dispersive X-Ray Spectrometers 63 4.2.1 Data Acquisition 63 4.2.2 Resolution 64 4.2.2.1 Comparison of Wavelength- and Energy-Dispersive Spectrometry 64 4.2.2.2 Resolution of WDS Instruments 66 4.2.2.3 Resolution of EDS Instruments 68 4.2.3 Detection Efficiency 70 4.2.4 Count Rate Capability 71 4.2.4.1 Optimum Throughput in ED Spectrometers 71 4.2.4.2 Saturation Effects in WDSs 72 4.2.4.3 Optimal Sensitivity of ED Spectrometers 73 4.2.4.4 Effect of the Pulse Throughput on the Measuring Time 74 4.2.5 Radiation Flux 75 4.2.6 Spectra Artifacts 76 4.2.6.1 Escape Peaks 76 4.2.6.2 Pile-Up Peak 77 4.2.6.3 Diffraction Peaks 77 4.2.6.4 Shelf and Tail 79 4.2.7 Mechanical Design and Operating Costs 79 4.2.8 Setting Parameters 80 4.3 Type of Instruments 80 4.3.1 ED Instruments 81 4.3.1.1 Handheld Instruments 82 4.3.1.2 Portable Instruments 83 4.3.1.3 Tabletop Instruments 84 4.3.2 Wavelength-Dispersive Instruments 85 4.3.2.1 Sequential Spectrometers 85 4.3.2.2 Multichannel Spectrometers 87 4.3.3 Special Type X-Ray Spectrometers 87 4.3.3.1 Total Reflection Instruments 88 4.3.3.2 Excitation by Monoenergetic Radiation 90 4.3.3.3 Excitation with Polarized Radiation 91 4.3.3.4 Instruments for Position-Sensitive Analysis 93 4.3.3.5 Macro X-Ray Fluorescence Spectrometer 94 4.3.3.6 Micro X-Ray Fluorescence with Confocal Geometry 95 4.3.3.7 High-Resolution X-Ray Spectrometers 96 4.3.3.8 Angle Resolved Spectroscopy – Grazing Incidence and Grazing Exit 96 4.4 Commercially Available Instrument Types 98 5 Measurement and Evaluation of X-ray Spectra 99 5.1 Information Content of the Spectra 99 5.2 Procedural Steps to Execute a Measurement 101 5.3 Selecting the Measurement Conditions 102 5.3.1 Optimization Criteria for the Measurement 102 5.3.2 Tube Parameters 103 5.3.2.1 Target Material 103 5.3.2.2 Excitation Conditions 104 5.3.2.3 Influencing the Energy Distribution of the Primary Spectrum 105 5.3.3 Measurement Medium 107 5.3.4 Measurement Time 108 5.3.4.1 Measurement Time and Statistical Error 108 5.3.4.2 Measurement Strategies 108 5.3.4.3 Real and Live Time 109 5.3.5 X-ray Lines 110 5.4 Determination of Peak Intensity 112 5.4.1 Intensity Data 112 5.4.2 Treatment of Peak Overlaps 112 5.4.3 Spectral Background 114 5.5 Quantification Models 117 5.5.1 General Remarks 117 5.5.2 Conventional Calibration Models 118 5.5.3 Fundamental Parameter Models 121 5.5.4 Monte Carlo Quantifications 124 5.5.5 Highly Precise Quantification by Reconstitution 124 5.5.6 Evaluation of an Analytical Method 126 5.5.6.1 Degree of Determination 126 5.5.6.2 Working Range, Limits of Detection (LOD) and of Quantification 127 5.5.6.3 Figure of Merit 129 5.5.7 Comparison of the Various Quantification Models 129 5.5.8 Available Reference Materials 131 5.5.9 Obtainable Accuracies 132 5.6 Characterization of Layered Materials 133 5.6.1 General Form of the Calibration Curve 133 5.6.2 Basic Conditions for Layer Analysis 135 5.6.3 Quantification Models for the Analysis of Layers 138 5.7 Chemometric Methods for Material Characterization 140 5.7.1 Spectra Matching and Material Identification 141 5.7.2 Phase Analysis 141 5.7.3 Regression Methods 143 5.8 Creation of an Application 143 5.8.1 Analysis of Unknown Sample Qualities 143 5.8.2 Repeated Analyses on Known Samples 144 6 Analytical Errors 149 6.1 General Considerations 149 6.1.1 Precision of a Measurement 151 6.1.2 Long-Term Stability of the Measurements 153 6.1.3 Precision and Process Capability 154 6.1.4 Trueness of the Result 156 6.2 Types of Errors 156 6.2.1 Randomly Distributed Errors 157 6.2.2 Systematic Errors 158 6.3 Accounting for Systematic Errors 159 6.3.1 The Concept of Measurement Uncertainties 159 6.3.2 Error Propagation 160 6.3.3 Determination of Measurement Uncertainties 161 6.3.3.1 Bottom-Up Method 161 6.3.3.2 Top-Down Method 162 6.4 Recording of Error Information 164 7 Other Element Analytical Methods 167 7.1 Overview 167 7.2 Atomic Absorption Spectrometry (AAS) 168 7.3 Optical Emission Spectrometry 169 7.3.1 Excitation with a Spark Discharge (OES) 169 7.3.2 Excitation in an Inductively Coupled Plasma (ICP-OES) 170 7.3.3 Laser-Induced Breakdown Spectroscopy (LIBS) 171 7.4 Mass Spectrometry (MS) 172 7.5 X-Ray Spectrometry by Particle Excitation (SEM-EDS, PIXE) 173 7.6 Comparison of Methods 175 8 Radiation Protection 177 8.1 Basic Principles 177 8.2 Effects of Ionizing Radiation on Human Tissue 178 8.3 Natural Radiation Exposure 179 8.4 Radiation Protection Regulations 181 8.4.1 Legal Regulations 181 9 Analysis of Homogeneous Solid Samples 183 9.1 Iron Alloys 183 9.1.1 Analytical Problem and Sample Preparation 183 9.1.2 Analysis of Pig and Cast Iron 184 9.1.3 Analysis of Low-Alloy Steel 185 9.1.4 Analysis of High-Alloy Steel 187 9.2 Ni–Fe–Co Alloys 188 9.3 Copper Alloys 189 9.3.1 Analytical Task 189 9.3.2 Analysis of Compact Samples 189 9.3.3 Analysis of Dissolved Samples 189 9.4 Aluminum Alloys 191 9.5 Special Metals 192 9.5.1 Refractories 192 9.5.1.1 Analytical Problem 192 9.5.1.2 Sample Preparation of Hard Metals 192 9.5.1.3 Analysis of Hard Metals 193 9.5.2 Titanium Alloys 194 9.5.3 Solder Alloys 194 9.6 Precious Metals 195 9.6.1 Analysis of Precious Metal Jewelry 195 9.6.1.1 Analytical Task 195 9.6.1.2 Sample Shape and Preparation 196 9.6.1.3 Analytical Equipment 197 9.6.1.4 Accuracy of the Analysis 198 9.6.2 Analysis of Pure Elements 198 9.7 Glass Material 199 9.7.1 Analytical Task 199 9.7.2 Sample Preparation 200 9.7.3 Measurement Equipment 202 9.7.4 Achievable Accuracies 202 9.8 Polymers 203 9.8.1 Analytical Task 203 9.8.2 Sample Preparation 204 9.8.3 Instruments 205 9.8.4 Quantification Procedures 205 9.8.4.1 Standard-Based Methods 205 9.8.4.2 Chemometric Methods 206 9.9 Abrasion Analysis 209 10 Analysis of Powder Samples 213 10.1 Geological Samples 213 10.1.1 Analytical Task 213 10.1.2 Sample Preparation 214 10.1.3 Measurement Technique 215 10.1.4 Detection Limits and Trueness 215 10.2 Ores 216 10.2.1 Analytical Task 216 10.2.2 Iron Ores 216 10.2.3 Mn, Co, Ni, Cu, Zn, and Pb Ores 217 10.2.4 Bauxite and Alumina 218 10.2.5 Ores of Precious Metals and Rare Earths 219 10.3 Soils and Sewage Sludges 221 10.3.1 Analytical Task 221 10.3.2 Sample Preparation 221 10.3.3 Measurement Technology and Analytical Performance 222 10.4 Quartz Sand 223 10.5 Cement 223 10.5.1 Analytical Task 223 10.5.2 Sample Preparation 224 10.5.3 Measurement Technology 225 10.5.4 Analytical Performance 226 10.5.5 Determination of Free Lime in Clinker 227 10.6 Coal and Coke 227 10.6.1 Analytical Task 227 10.6.2 Sample Preparation 228 10.6.3 Measurement Technology and Analytical Performance 229 10.7 Ferroalloys 230 10.7.1 Analytical Task 230 10.7.2 Sample Preparation 230 10.7.3 Analysis Technology 232 10.7.4 Analytical Performance 234 10.8 Slags 235 10.8.1 Analytical Task 235 10.8.2 Sample Preparation 235 10.8.3 Measurement Technology and Analytical Accuracy 236 10.9 Ceramics and Refractory Materials 237 10.9.1 Analytical Task 237 10.9.2 Sample Preparation 237 10.9.3 Measurement Technology and Analytical Performance 238 10.10 Dusts 239 10.10.1 Analytical Problem and Dust Collection 239 10.10.2 Measurement 242 10.11 Food 242 10.11.1 Analytical Task 242 10.11.2 Monitoring of Animal Feed 243 10.11.3 Control of Infant Food 244 10.12 Pharmaceuticals 245 10.12.1 Analytical Task 245 10.12.2 Sample Preparation and Analysis Method 245 10.13 Secondary Fuels 246 10.13.1 Analytical Task 246 10.13.2 Sample Preparation 247 10.13.2.1 Solid Secondary Raw Materials 247 10.13.2.2 Liquid Secondary Raw Materials 249 10.13.3 Instrumentation and Measurement Conditions 250 10.13.4 Measurement Uncertainties in the Analysis of Solid Secondary Raw Materials 251 10.13.5 Measurement Uncertainties for the Analysis of Liquid Secondary Raw Materials 252 11 Analysis of Liquids 253 11.1 Multielement Analysis of Liquids 254 11.1.1 Analytical Task 254 11.1.2 Sample Preparation 254 11.1.3 Measurement Technology 254 11.1.4 Quantification 255 11.2 Fuels and Oils 255 11.2.1 Analysis of Toxic Elements in Fuels 256 11.2.1.1 Measurement Technology 256 11.2.1.2 Analytical Performance 258 11.2.2 Analysis of Additives in Lubricating Oils 258 11.2.3 Identification of Abrasive Particles in Used Lubricants 260 11.3 Trace Analysis in Liquids 261 11.3.1 Analytical Task 261 11.3.2 Preparation by Drying 261 11.3.3 Quantification 262 11.4 Special Preparation Techniques for Liquid Samples 263 11.4.1 Determination of Light Elements in Liquids 263 11.4.2 Enrichment Through Absorption and Complex Formation 264 12 Trace Analysis Using Total Reflection X-Ray Fluorescence 267 12.1 Special Features of TXRF 267 12.2 Sample Preparation for TXRF 269 12.3 Evaluation of the Spectra 271 12.3.1 Spectrum Preparation and Quantification 271 12.3.2 Conditions for Neglecting the Matrix Interaction 272 12.3.3 Limits of Detection 273 12.4 Typical Applications of the TXRF 274 12.4.1 Analysis of Aqueous Solutions 274 12.4.1.1 Analytical Problem and Preparation Possibilities 274 12.4.1.2 Example: Analysis of a Fresh Water Standard Sample 275 12.4.1.3 Example: Detection of Mercury in Water 277 12.4.2 Analysis of the Smallest Sample Quantities 278 12.4.2.1 Example: Pigment Analysis 278 12.4.2.2 Example: Aerosol Analysis 279 12.4.2.3 Example: Analysis of Nanoparticles 279 12.4.3 Trace Element Analysis on Human Organs 280 12.4.3.1 Example: Analysis of Blood and Blood Serum 280 12.4.3.2 Example: Analysis of Trace Elements in Body Tissue 282 12.4.4 Trace Analysis of Inorganic and Organic Chemical Products 283 12.4.5 Analysis of Semiconductor Electronics 284 12.4.5.1 Ultra-Trace Analysis on SiWafers with VPD 284 12.4.5.2 Depth Profile Analysis by Etching 285 13 Nonhomogeneous Samples 287 13.1 Measurement Modes 287 13.2 Instrument Requirements 288 13.3 Data Evaluation 290 14 Coating Analysis 291 14.1 Analytical Task 291 14.2 Sample Handling 292 14.3 Measurement Technology 293 14.4 The Analysis Examples of Coated Samples 294 14.4.1 Single-Layer Systems: Emission Mode 294 14.4.2 Single-Layer Systems: Absorption Mode 297 14.4.3 Single-Layer Systems: Relative Mode 298 14.4.3.1 Analytical Problem 298 14.4.3.2 Variation of the Specified Working Distance 298 14.4.3.3 Sample Size and Spot Size Mismatch 299 14.4.3.4 Non-detectable Elements in the Layer: NiP Layers 300 14.4.4 Characterization of Ultrathin Layers 302 14.4.5 Multilayer Systems 304 14.4.5.1 Layer Systems 304 14.4.5.2 Measurement Technology 305 14.4.5.3 Example: Analysis of CIGS Solar Cells 305 14.4.5.4 Example: Analysis of Solder Structures 306 14.4.6 Samples with Unknown Coating Systems 307 14.4.6.1 Preparation of Cross Sections 308 14.4.6.2 Excitation at Grazing Incidence with Varying Angles 309 14.4.6.3 Measurement in Confocal Geometry 311 15 Spot Analyses 313 15.1 Particle Analyses 313 15.1.1 Analytical Task 313 15.1.2 Sample Preparation 314 15.1.3 Analysis Technology 315 15.1.4 Application Example:Wear Particles in Used Oil 315 15.1.5 Application Example: Identification of Glass Particles by Chemometrics 316 15.2 Identification of Inclusions 318 15.3 Material Identification with Handheld Instruments 318 15.3.1 Analytical Tasks 318 15.3.2 Analysis Technology 319 15.3.3 Sample Preparation and Test Conditions 320 15.3.4 Analytical Accuracy 320 15.3.5 Application Examples 321 15.3.5.1 Example: Lead in Paint 321 15.3.5.2 Example: Scrap Sorting 321 15.3.5.3 Example: Material Inspection and Sorting 322 15.3.5.4 Example: Precious Metal Analysis 322 15.3.5.5 Example: Prospecting and Screening in Geology 323 15.3.5.6 Example: Investigation of Works of Art 323 15.4 Determination of Toxic Elements in Consumer Products: RoHS Monitoring 324 15.4.1 Analytical Task 324 15.4.2 Analysis Technology 325 15.4.3 Analysis Accuracy 327 15.5 Toxic Elements in Toys: Toys Standard 328 15.5.1 Analytical Task 328 15.5.2 Sample Preparation 328 15.5.3 Analysis Technology 330 16 Analysis of Element Distributions 331 16.1 General Remarks 331 16.2 Measurement Conditions 332 16.3 Geology 333 16.3.1 Samples Types 333 16.3.2 Sample Preparation and Positioning 333 16.3.3 Measurements on Compact Rock Samples 334 16.3.3.1 Sum Spectrum and Element Distributions 334 16.3.3.2 Object Spectra 335 16.3.3.3 Treatment of Line Overlaps 336 16.3.3.4 Maximum Pixel Spectrum 339 16.3.4 Thin Sections of Geological Samples 340 16.4 Electronics 342 16.5 Archeometric Investigations 344 16.5.1 Analytical Tasks 344 16.5.2 Selection of an Appropriate Spectrometer 346 16.5.3 Investigations of Coins 347 16.5.4 Investigations of Painting Pigments 349 16.6 Homogeneity Tests 350 16.6.1 Analytical Task 350 16.6.2 Homogeneity Studies Using Distribution Analysis 351 16.6.3 Homogeneity Studies Using Multi-point Measurements 352 17 Special Applications of the XRF 355 17.1 High-Throughput Screening and Combinatorial Analysis 355 17.1.1 High-Throughput Screening 355 17.1.2 Combinatorial Analysis for Drug Development 357 17.2 Chemometric Spectral Evaluation 358 17.3 High-Resolution Spectroscopy for Speciation Analysis 361 17.3.1 Analytical Task 361 17.3.2 Instrument Technology 361 17.3.3 Application Examples 362 17.3.3.1 Analysis of Different Sulfur Compounds 362 17.3.3.2 Speciation of Aluminum Inclusions in Steel 363 17.3.3.3 Determination of SiO2 in SiC 365 18 Process Control and Automation 367 18.1 General Objectives 367 18.2 Off-Line and At-Line Analysis 369 18.2.1 Sample Supply and Analysis 369 18.2.2 Automated Sample Preparation 371 18.3 In-Line and On-Line Analysis 376 19 Quality Management and Validation 379 19.1 Motivation 379 19.2 Validation 380 19.2.1 Parameters 384 19.2.2 Uncertainty 385 Appendix A Tables 387 Appendix B Important Information 419 B.1 Coordinates of Main Manufacturers of Instruments and Preparation Tools 419 B.2 Main Suppliers of Standard Materials 422 B.2.1 Geological Materials and Metals 422 B.2.2 Stratified Materials 423 B.2.3 Polymer Standards 424 B.2.4 High Purity Materials 424 B.2.5 Precious Metal Alloys 425 B.3 Important Websites 425 B.3.1 Information About X-Ray Analytics and Fundamental Parameters 425 B.3.2 Information About Reference Materials 426 B.3.3 Scientific Journals 427 B.4 Laws and Acts, Which Are Important for X-Ray Fluorescence 427 B.4.1 Radiation Protection 427 B.4.2 Regulations for Environmental Control 428 B.4.3 Regulations for Performing Analysis 428 B.4.4 Use of X-ray Fluorescence for the Chemical Analysis 428 B.4.4.1 General Regulations 428 B.4.4.2 Analysis of Minerals 429 B.4.4.3 Analysis of Oils, Liquid Fuels, Grease 430 B.4.4.4 Analysis of Solid Fuels 432 B.4.4.5 Coating Analysis 433 B.4.4.6 Metallurgy 433 B.4.4.7 Analysis of Electronic Components 434 References 435 Index 453